Detecting packet loss on a rtsp stream receiver

[Federico Zamperini]

Hi,
	i'm facing the problem of detecting network packet loss on the receiver 
side (a  rtsp/rtp stream receiver); I'd like to switch to a backup video 
stored on the client in case of poor video performance.
One solution I'm trying is handling qos bus messages and counting 
dropped buffers, which actually affects the output (artifatcs).
I was wondering if it was even possibile to peek RTCP statistics, but I 
couldn't get the children of the rtspsrc (I'm not a gstreamer expert -- 
any help accepted ;-)).
Does anyone here have other better solutions to suggest?
Thanks

Federico